Buggy code:
public class Javadoc extends Task implements ExecOutputHandler { private Commandline m_command = new Commandline ( ) ; private Path m_sourcePath ; private File m_destDir ; private ArrayList m_sourceFiles = new ArrayList ( ) ; private ArrayList m_packageNames = new ArrayList ( 5 ) ; private ArrayList m_excludePackageNames = new ArrayList ( 1 ) ; private boolean m_author = true ; private boolean m_version = true ; private DocletInfo m_doclet ; private Path m_classpath ; private Path m_bootclasspath ; private String m_group ; private ArrayList m_compileList = new ArrayList ( 10 ) ; private String m_packageList ; private ArrayList m_links = new ArrayList ( 2 ) ; private ArrayList m_groups = new ArrayList ( 2 ) ; private boolean m_useDefaultExcludes = true ; private Html m_doctitle ; private Html m_header ; private Html m_footer ; private Html m_bottom ; private boolean m_useExternalFile ; private File m_tmpList ; public void setAccess ( AccessType at ) { } public void setAdditionalparam ( String add ) throws TaskException { <START_BUG> m_command . createArgument ( ) . setLine ( add ) ; <END_BUG> } public void setAuthor ( boolean src ) { } public void setBootclasspath ( Path src ) throws TaskException { } public void setBottom ( String src ) { } public void setCharset ( String src ) { } public void setClasspath ( Path src ) throws TaskException { } public void setDefaultexcludes ( boolean useDefaultExcludes ) { } public void setDestdir ( File dir ) { } public void setDocencoding ( String enc ) { } public void setDoclet ( String src ) { } public void setDocletPath ( Path src ) throws TaskException { } public void setDoctitle ( String src ) { } public void setEncoding ( String enc ) { } public void setExcludePackageNames ( String src ) { } public void setExtdirs ( String src ) { } public void setFooter ( String src ) { } public void setGroup ( String src ) { } public void setHeader ( String src ) { } public void setHelpfile ( File f ) { } public void setLink ( String src ) { } public void setLinkoffline ( String src ) throws TaskException { } public void setLocale ( String src ) { } public void setMaxmemory ( final String max ) { } public void setNodeprecated ( boolean b ) { } public void setNodeprecatedlist ( boolean b ) { } public void setNohelp ( boolean b ) { } public void setNoindex ( boolean b ) { } public void setNonavbar ( boolean b ) { } public void setNotree ( boolean b ) { } public void setOld ( boolean b ) { } public void setOverview ( File f ) { } public void setPackage ( boolean b ) { } public void setPackageList ( String src ) { } public void setPackagenames ( String src ) { } public void setPrivate ( boolean b ) { } public void setProtected ( boolean b ) { } public void setPublic ( boolean b ) { } public void setSerialwarn ( boolean b ) { } public void setSourcefiles ( String src ) throws TaskException { } public void setSourcepath ( Path src ) throws TaskException { } public void setSplitindex ( boolean b ) { } public void setStylesheetfile ( File f ) { } public void setUse ( boolean b ) { } public void setUseExternalFile ( boolean b ) { } public void setVerbose ( boolean b ) { } public void setVersion ( boolean src ) { } public void setWindowtitle ( String src ) { } public void addBottom ( Html text ) { } public void addDoctitle ( Html text ) { } public void addExcludePackage ( PackageName pn ) { } public void addFooter ( Html text ) { } public void addHeader ( Html text ) { } public void addPackage ( PackageName pn ) { } public void addSource ( SourceFile sf ) throws TaskException { } public Path createBootclasspath ( ) throws TaskException { } public Path createClasspath ( ) throws TaskException { } public DocletInfo createDoclet ( ) { } public GroupArgument createGroup ( ) { } public LinkArgument createLink ( ) { } public Path createSourcepath ( ) throws TaskException { } public void execute ( ) throws TaskException { } private String getJavadocExecutableName ( ) { } private void add12ArgIfNotEmpty ( String key , String value ) { } private void addArgIf ( boolean b , String arg ) { } private void evaluatePackages ( Commandline toExecute , Path sourcePath , ArrayList packages , ArrayList excludePackages ) throws TaskException { } public void stdout ( final String line ) { } public void stderr ( final String line ) { } }

Fix:
m_command . addLine ( add ) ;